1 files changed, 33 insertions, 0 deletions
diff --git a/3760/CH2/EX2.15/Ex2_15.sce b/3760/CH2/EX2.15/Ex2_15.sce
new file mode 100644
index 000000000..e0f060796
--- /dev/null
+++ b/3760/CH2/EX2.15/Ex2_15.sce
@@ -0,0 +1,33 @@
+clc;
+B=[ 0.2 0.4 0.6 0.8 1 1.2];
+H=[ 50 100 160 225 300 400];
+plot(H,B); 
+xlabel('magnetic field intensity');
+ylabel('magnetic flux density');
+title('B-H curve');
+p=0.2; // force exerted by spring
+g1=0.5*10^-2; // air gap length
+g2=0.1*10^-2; // reduced gap length after coil is energised
+n=2000; // coil turns
+l=0.2; // mean length of magnetic iron path
+A=0.2*10^-4; // area of cross-section
+g=9.81; // acceleration due to gravity
+l1=6; // gap length
+l2=3; // gap length between spring and core
+uo=4*%pi*10^-7; // free space permeability
+disp('case a');
+fe=(p*g*l2)/l1; // electromagnetic torque
+Bg=sqrt((2*fe*uo)/A); // air gap flux density
+printf('Air gap flux density is %f T\n',Bg);
+// corresponding to value of Bg from B-H curve H is 
+Hg=87.7; // magnetic flux intensity
+ATi=l*Hg; // total ampere turn for iron path
+ATg=(Bg*g1)/uo; // ampere turn for air gap
+AT=ATi+ATg; // total ampere turns
+ie=AT/n;
+printf('Exciting current required to close the armature relay is %f A\n',ie);
+disp('case b');
+ATg=(Bg*g2)/uo; // ampere turn for air gap
+AT=ATi+ATg; // total ampere turns
+ie=AT/n;
+printf('Exciting current required to keep the armature closed is %f A\n',ie);